System and method for affixing reference dots with respect to modeling impression materials

ABSTRACT

A holder to facilitate optical data acquisition includes a float portion that extends from a handle portion to at least partially support the handle portion with respect to a surface of the liquid modeling impression material. A method of optical data acquisition includes communicating a liquid modeling impression material into a non-line of sight feature of a workpiece and immersing a portion of a holder into the liquid modeling impression material.

CROSS-REFERENCE TO RELATED APPLICATION

The instant application is a divisional application of U.S. patentapplication Ser. No. 14/872,362 filed Oct. 1, 2015.

BACKGROUND

The present disclosure relates to an optical measurement system and,more particularly, to a holder for non-line of sight features.

Reverse engineering components often employs a white-light scanningtechnique called ATOS (Advanced Topometric Sensor). This scanning isline of sight only. To capture non-line of sight features such as slots,a modeling impression material can be used to form impressions of thenon-line of sight hidden area to be scanned and aligned back into themain workpiece scan at a later date. Alignment is facilitated throughthe use of reference dots affixed to the surface of the modelingimpression material.

One recent type of modeling impression material is a replicator materialthat flows into the non-line of sight feature like water, and withinminutes, sets into shape for subsequent scanning. This liquid typemodeling impression material is readily poured into the non-line ofsight features but is not conducive to application of reference dotsonto the surface when liquid, nor post-hardening, as the reference dotsdo not affix well to the solidified but relatively soft rubber-likesurface.

SUMMARY

A holder to facilitate optical data acquisition according to onedisclosed non-limiting embodiment of the present disclosure can includea handle portion; and a float portion to at least partially support thehandle portion with respect to a surface of a liquid modeling impressionmaterial.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the handle portion is sized to receive at leastthree reference dots.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the handle portion includes a cap portiontransverse to a body portion.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the handle portion includes a cap portionperpendicular to a body portion.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the cap portion is sized to receive at least threereference dots.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein a mesh area adjacent to the float portion, the mesharea at least partially immersible within the liquid modeling impressionmaterial when the float portion is on the surface of the liquid modelingimpression material.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein an anchor portion opposite the handle portion.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the anchor portion forms a platform receivablewithin the liquid modeling impression material.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the holder is additively manufactured.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the holder is configured to be at least partiallyreceived within a particular non-line of sight feature of a workpiece.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the holder includes a flow channel to communicatethe modeling impression material into the non-line of sight feature.

A holder to facilitate optical data acquisition according to anotherdisclosed non-limiting embodiment of the present disclosure can includea handle portion; an anchor portion to be immersed in a liquid modelingimpression material; and a float portion between the handle portion andthe anchor portion, the float portion operable to at least partiallysupport the handle portion with respect to a surface of the liquidmodeling impression material.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the handle portion is sized to receive at leastthree reference dots.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein a mesh area adjacent to the anchor portion, themesh area at least partially receivable within the liquid modelingimpression material.

A method of optical data acquisition according to another disclosednon-limiting embodiment of the present disclosure can includecommunicating a liquid modeling impression material into a non-line ofsight feature of a workpiece; and immersing a portion of a holder intothe liquid modeling impression material.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the portion of the holder immersed in the liquidmodeling impression material includes an anchor portion.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the portion of the holder immersed in the liquidmodeling impression includes a mesh area.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein the portion of the holder immersed in the liquidmodeling impression is separated from a handle portion by a floatportion.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein at least a portion of the float portion floats onthe surface of the liquid modeling impression material.

A further embodiment of any of the embodiments of the present disclosuremay include, wherein communicating the liquid modeling impressionmaterial through the holder then into the non-line of sight feature ofthe workpiece.

The foregoing features and elements may be combined in variouscombinations without exclusivity, unless expressly indicated otherwise.These features and elements as well as the operation thereof will becomemore apparent in light of the following description and the accompanyingdrawings. It should be understood, however, the following descriptionand drawings are intended to be exemplary in nature and non-limiting.

BRIEF DESCRIPTION OF THE DRAWINGS

Various features will become apparent to those skilled in the art fromthe following detailed description of the disclosed non-limitingembodiments. The drawings that accompany the detailed description can bebriefly described as follows:

FIG. 1 is a schematic view of an optical data acquisition system;

FIG. 2 is a schematic view of an example workpiece;

FIG. 3 is a schematic view of a holder to facilitate optical dataacquisition within the workpiece;

FIG. 4 is a perspective view of a holder to facilitate optical dataacquisition;

FIG. 5 is a perspective view of a holder affixed within modelingimpression material;

FIG. 6 is a schematic view of a holder according to another embodiment;and

FIG. 7 is a method of optical data acquisition of a non-line of sightfeature with the holder.

DETAILED DESCRIPTION

FIG. 1 schematically illustrates an optical data acquisition system 20such as ATOS (Advanced Topometric Sensor) system manufactured by GOM mbHof Braunschweig, Germany. It should be appreciated that various systemsoptical scanner which scans three-dimensional objects and converts theimages to high density point clouds may be utilized.

The optical data acquisition system 20 generally includes a lightprojector 22, a first image capture device 24, such as a digital camera,at a first location 26, a second image capture device 28 at secondlocation 30 and a control subsystem 32. It should be appreciated thatalthough particular components are separately defined, each or any ofthe components may be otherwise combined or segregated via hardwareand/or software.

The optical data acquisition system 20 projects a light pattern onto aworkpiece 100 such as, in the illustrated non-limiting embodiment, arotor disk (FIG. 2). The two image capture devices 24, 28 simultaneouslycapture images from the two measurement cameras from different angles.This stereo-setup supports accurate 3D capturing of the workpiece 10.

A multitude of reference dots 34 randomly placed on or around theworkpiece 10 may also be utilized to form a reference system to matchmeasurements from multiple angles as the workpiece 10 is rotated on aturntable 36. That is, the size and orientation of the reference dots34, which are of a know size and shape, are imaged then utilized by theoptical data acquisition system 20 to provide a frame of reference.

The optical data acquisition system 20 utilizes a minimum of threereference dots 34 within a limited line of sight volume provided by thetwo image capturing device 24, 28 in any given measurement to determinea point cloud of X, Y, Z coordinates to provide the three-dimensionaldata acquisition. The control subsystem 32 merges all the images of theencoded dots 34 to triangulate and generate a 3-dimensional relationshipand location of all the encoded dots 34. Through triangulation, asurface map of the workpiece 10 is readily constructed by the controlsubsystem 32 to provide accurate measurement and capture of the shapeand size of the visible surface of the workpiece 10.

With reference to FIG. 2, the workpiece 10 often includes non-line ofsight features 12 such as a vane hook slot in a gas turbine engine case.It should be appreciated that various non-line of sight features 12 maybenefit herefrom. The non-line of sight features 12 may be imagedthrough the use of a modeling impression material 40 such as, forexample, “ScanRubber.” ScanRubber is a compound that flows into thefeature like water, and within minutes, sets into a hardened solid forsubsequent scanning. Although effective, the unique liquid applicationobviates the setting reference dots onto the surface, as well asapplication post-hardening, as the reference dots do not affix well tothe ScanRubber surface.

The modeling impression material 40 is used to fill the non-line ofsight features 12, removed after solidifying, then is scanned andaligned back into the overall scan of the workpiece 10. The modelingimpression material 40 is essentially a liquid when communicated intothe non-line of sight features 12 to facilitate an accuraterepresentation. Later alignment of the non-line of sight features 12 tothe surface map of the workpiece 10 is facilitated through the use ofreference dots 34.

With reference to FIG. 3, to facilitate placement of the reference dots34 with respect to the non-line of sight features 12, a holder 50 uponwhich reference dots 34 are placed is located into the modelingimpression material 40 while the modeling impression material 40 isstill liquid. In one embodiment, the holder 50 at least partially on theliquid modeling impression material 40 and it then retained therein uponsolidification.

With reference to FIG. 4, the holder 50 generally includes, an anchorportion 52, a mesh area 54, a float portion 56, and a handle portion 58.The holder 50 may be generic in shape for common non-line of sightfeatures such as slots, apertures, conics, etc., alternatively, theholder 50 may be specifically shaped for single use non-line of sightfeatures and readily manufactured via, for example, additivemanufacturing. As the holder 50 is essentially non-structural, theholder 50 need only be retained in fixed position with respect to themodeling impression material 40 to provide a reference frame for thereference dots 34, and need not last much longer than the relativelyshort-lived modeling impression material 40. The holder 50 may bemanufactured of materials such as plastic or other relativelyinexpensive materials conducive to additive manufacturing.

The anchor portion 52 may be relatively larger, or shaped differently,than the mesh area 54 to facilitate engagement with the modelingimpression material 40 (FIG. 5). The anchor portion 52, in oneembodiment, may be a rectilinear platform that extends from a lowerportion of the holder 50. The mesh area 54 may include numerousapertures 60 and located adjacent the anchor portion 52 and/or the floatportion 56. The apertures 60 of the mesh area 54 permits the modelingimpression material 40 to flow therethrough in the liquid state then bereadily embedded therein upon solidification. The mesh area 54 may be ofvarious configurations and may optionally be utilized as additionalretention structure with the anchor portion 52.

The float portion 56 is located between the anchor portion 53 and thehandle portion 58. The float portion 56, in one embodiment, may be aplatform that extends from a lower portion of the holder 50 adjacent tothe mesh area 54. The float portion 56 is sized and shaped to remaingenerally upon the surface of the modeling impression material 40 whilein the liquid state such that the handle portion 58 remains above thesurface (FIG. 5).

The handle portion 58 extends above the float portion 56 and may be ofvarious configurations and shapes. In one embodiment, the handle portion58 includes a cap portion 62 transverse to a body portion 64 thatincludes at least some of the mesh area 54. The cap portion 62 may beperpendicular to the body portion 64 to facilitate location of thereference dots 34 in two different measurement planes. It should beappreciated that any number of reference dots 34 may be located on theholder 50 to facilitate integration of the non-line of sight features 12back into the workpiece 10 via reference dots on both the holder 50 andthe workpiece 10 (FIG. 3). That is, the holder 50 forms a new surfaceinside or above the modeling impression material 40 for use as areference dot plane as well as a handle portion for grasping, moving,and transporting the solidified material 40 to minimize handling andpotential distortion thereof.

With reference to FIG. 6, another disclosed non-limiting embodiment of aholder 50A include flow channels 70 to inject the modeling impressionmaterial 40 into the into the non-line of sight features 12 of theworkpiece 10. The flow channels 70 may include one or more ports 72 inthe cap portion 62A with one or more outlets 74 in the anchor portion52A. It should be appreciated that various flow channel 70 paths may beutilized to facilitate injection of the liquid modeling impressionmaterial 40 into the into the non-line of sight features 12 which, forexample, may be relatively difficult to access.

With reference to FIG. 7, one disclosed non-limiting embodiment of amethod 200 for use of the holder 50 initially includes scanning theworkpiece 10 and the reference dots thereon (step 210). Next, themodeling impression material 40 is injected into the non-line of sightfeatures 12 of the workpiece 10 (step 220). Next, the holder 50 islocated in the still liquid modeling impression material 40 such thatthe float portion 56 remains generally upon the surface of the modelingimpression material 40 while in the liquid state such that the handleportion 58 remains above the surface (step 230; FIG. 3). The anchorportion 52 is located below the surface and the mesh area 54 at leastpartially below the surface to embed into the modeling impressionmaterial 40 upon hardening. It should be appreciated that the injectionof the liquid modeling impression material 40 into the non-line of sightfeatures 12 may alternatively be performed simultaneous, or subsequent,to location of the holder 50 into the respective non-line of sightfeature 12.

The workpiece 10 with the holders 50 in place is then again scanned(step 240). As the holders 50 include reference dots 34, the relativeposition of each the holder 50 is thereby oriented to the workpiece.

The holder 50, which is embedded within the solidified modelingimpression material 40, is then removed from the non-line of sightfeatures 12 (step 250). The solidified modeling impression material 40,provides a positive cast of the negative non-line of sight features 12to provide the exact contours thereof.

Each solidified modeling impression material 40 representative of therespective non-line of sight feature 12 and the associated holder 50 isthen separately scanned (step 260). The reference dots 34 again providea frame of reference for each solidified modeling impression material 40representative of the respective non-line of sight feature 12. That is,the holder 50 positions the reference dots 34 to orient the optical dataacquisition system 20 at areas otherwise not sufficient surface area forthe reference dots 34 s

The captured scan data for the solidified modeling impression material40 representative of the respective non-line of sight feature 12 is thenintegrated in the predefined reference marker framework of the workpiece10 (step 270). That is, the exact contours of the non-line of sightfeature 12 is integrated back into the workpiece 10.

The holder 50 beneficially provides surface inside or above the modelingimpression material for use as a reference dot plane as well as a handleportion for grasping, moving, and transporting the modeling material.

The use of the terms “a,” “an,” “the,” and similar references in thecontext of description (especially in the context of the followingclaims) are to be construed to cover both the singular and the plural,unless otherwise indicated herein or specifically contradicted bycontext. The modifier “about” used in connection with a quantity isinclusive of the stated value and has the meaning dictated by thecontext (e.g., it includes the degree of error associated withmeasurement of the particular quantity). All ranges disclosed herein areinclusive of the endpoints, and the endpoints are independentlycombinable with each other. It should be appreciated that relativepositional terms such as “forward,” “aft,” “upper,” “lower,” “above,”“below,” and the like are with reference to normal operational attitudeand should not be considered otherwise limiting.

Although the different non-limiting embodiments have specificillustrated components, the embodiments of this invention are notlimited to those particular combinations. It is possible to use some ofthe components or features from any of the non-limiting embodiments incombination with features or components from any of the othernon-limiting embodiments.

It should be appreciated that like reference numerals identifycorresponding or similar elements throughout the several drawings. Itshould also be appreciated that although a particular componentarrangement is disclosed in the illustrated embodiment, otherarrangements will benefit herefrom.

Although particular step sequences are shown, described, and claimed, itshould be understood that steps may be performed in any order, separatedor combined unless otherwise indicated and will still benefit from thepresent disclosure.

The foregoing description is exemplary rather than defined by thelimitations within. Various non-limiting embodiments are disclosedherein, however, one of ordinary skill in the art would recognize thatvarious modifications and variations in light of the above teachingswill fall within the scope of the appended claims. It is therefore to beunderstood that within the scope of the appended claims, the disclosuremay be practiced other than as specifically described. For that reasonthe appended claims should be studied to determine true scope andcontent.

What is claimed:
 1. A method of optical data acquisition, comprising:scanning a workpiece and a multiple of reference dots thereon with anoptical data acquisition system; communicating a liquid modelingimpression material into a non-line of sight feature of a workpiece;immersing an anchor portion of a holder into the liquid modelingimpression material such that a float portion at least partiallysupports a handle portion with respect to a surface of the liquidmodeling impression material to position a multitude of reference dotson the handle portion such that the multitude of reference dots arevisible to the optical data acquisition system; scanning the workpiece,the holder, and the reference dots thereon with the optical dataacquisition system; removing the holder from the non-line of sightfeature with the solidified modeling impression material thereon, thesolidified modeling impression material provides a positive cast of thenegative non-line of sight feature to provide the exact contoursthereof; scanning the holder and the reference dots thereon afterremoval with the optical data acquisition system; and integrating thecaptured scan data for solidified modeling impression materialrepresentative of the respective non-line of sight feature into apredefined reference marker framework of the workpiece.
 2. The method asrecited in claim 1, further comprising additively manufacturing theholder with respect to the non-line of sight feature.